Also, vanilla fragrance can be effectively extracted from cow dung, and hamsters given Viagra cope better with jetlag.

These are among the bizarre but real findings that earned researchers Ig Nobel prizes this year.

Marc Abrahams, the creator of the awards, said the Ig Nobels are meant for discoveries or inventions that "make you laugh, and then make you think."

The winners collected their prizes last night at a ceremony at Harvard University in Cambridge, Massachusetts, with more than a thousand people in attendance.

Swords and "Aphrodisiac Bombs"

At the ceremony, sword swallower Dan Meyer inserted a long blade down his throat, then walked to the microphone and said "fank ooh" for the Ig Nobel Prize in Medicine.

Meyer and radiologist Brian Witcombe of the Gloucestershire Royal Hospital in England did a survey of sword swallowers to find out what kinds of injuries and complications these performers commonly suffered.

Although most of the performers were self-taught, they had surprisingly few complaints.

One common problem was "sword throat," an irritation usually caused by performing their act too often.

According to the study, published in the British Medical Journal, the few cases of more serious problems were often freak occurrences.